invisible buttons

In max 4 the pictctrl object used to present itself as a transparent button before you added an image to it, now in max 5 it seems to provide you with a generic image. I really want a transparent button for my project, I created a transparent .png file in photoshop and tried using that as the image file which worked for a while but has now turned jet black proving this method to be fairly unstable. Any work arounds / objects / options that I am missing? Many thanks!